Method and apparatus for treating textile yarn



NOV. 18, 1969 w, w wo ET AL 3,478,401

METHODfAND APPARATUS FOR TREATING TEXTILE YARN Filed Dec. 8, 1967 2 Sheets-Sheet 1 INVENTORS WILLIAM J. SCHRSQER I;JAM W. W'HITW T Nov. 18, 1969 J. w. WHITWORTH ETAL 3,478,401

METHOD AND APPARATUS FOR TREATING TEXTILE YARN Filed Dec. 8, 1967 2 Sheets-Sheet 2 INVENTORS WILLIAM J. SCHRODER AM 8 W. WHITWORTH XAZ/M ATTORNEY United States Patent 3,478,401 METHOD AND APPARATUS FOR TREATING TEXTILE YARN James W. Whitworth and William J. Schroder, Spartanburg, S.C., assi'gnors to Deen'ng Milliken Research Corporation, Spartanburg, S.C., a corporation of South Carolina Filed Dec. 8, 1967, Ser. No. 689,025

Int. Cl. D02j 11/00 US. CI. 28-62 18 Claims ABSTRACT OF THE DISCLOSURE A novel method of continuously processing a textile yarn comprises subjecting a yarn to a stream of gas, overfeeding the yarn to yarn advancing means under low tension, advancing the yarn by contact with a moving surface of the yarn advancing means, and subjecting the yarn to a gaseous atmosphere while the yarn is being advanced in contact with the moving surface; also, apparatus for such processing.

This invention relates to a method and apparatus for uniformly treating textile yarn and more particularly relates to a method and apparatus for processing textile yarn in the presence of a gaseous atmosphere.

In the manufacture of textile yarn, various operations or processing steps are often performed which create strains, stresses, etc., in the yarns. For example, in producing texturized yarn formed from thermoplastic materials, it is customary to subject the yarn to an operation such as edge crimping, stuffer box crimping, false twisting or similar processes to texture the yarn. Subsequent to such processing, it often is desirable to subject such yarn to a heat treatment under relatively low controlled tension prior to incorporation into tufted, woven or knitted fabrics, etc., in an attempt to develop crimp, stabilize or set the yarn. Heat treatment under reduced tension is believed to relieve or minimize the latent stresses previouslyformed in the yarn by various processing steps including drawing, crimping, bulking, etc. If these stresses remain in the yarn, excessive shrinkage or 'otherundesirable changes in the final fabric may result.

The heat treatment ,under the relatively low controlled tension, however, is employed to release or minimize these latent stresses under controlled conditions. As'an example of the visible change in the yarn during crimp development, a yarn which has been crimped bydrawing over an edge in a semi-relaxed or unrelaxed state appears to have only a small amount of crimp with the diameter of the individual fiber coils being quite large due to the immediate elastic recovery of the shrinkage phase. However, when the edge crimped yarn is subjected to an elevated temperature in a relaxed state, e.g., through the use of dry or moist heat, thefiber shrinks more on the innerface'of the helix. This development of the crimp causes the fibert'o change in appearance from large lazy coils to smaller coils.

In some applications it is essential that the yarn shortening be reduced to minimize excess shortening of the yarn after it is incorporated into a fabric to maximize 3,478,401 Patented Nov. 18, 1969 ice volves the heating of the crimped yarn at an elevated temperature under no tension whatsoever. However, this may produce too much contraction of the yarn, i.e., over development or excess shortening of the yarn.

A further problem encountered in previous attempts to continuously stabilize and develop textured yarns is that the tensions customarily encountered in the yarn with such operations tend to pull the texture, bulk or crimp, from the yarn thereby decreasing the desired textured effect. This problem is compounded at high speeds where it is difiicult to maintain uniform stabilization conditions, and also there is a tendency for a plurality of filaments to cling together so that the crimp therein remains in phase in each of the filaments thereby reducing the bulkiness of the yarn at points along its length. The presence of such non-uniform yarns in finished fabrics produces undesirable effects in the fabric.

In contrast to the previous unsuccessful attempts to uniformly stabilize and develop textile yarns, the present invention provides a novel method and apparatus for continuously processing textile yarns uniformly in the presence of a gaseous atmosphere.

In accordance with the present invention, a novel method of continuously processing a textile yarn comprises subjecting a yarn to a stream of gas, overfeeding the yarn to yarn advancing means under low tension, advancing the yarn by contact with a moving surface of the yarn advancing means, and subjecting the yarn to a gaseous atmosphere while the yarn is being advanced in contact with the movingsurface.

Yarns suitable for treatment in accordance with the method of the present invention include various types of yarn, both multifilament and monofilament yarns and include yarns formed from natural and synthetic fibers. Particularly useful are yarns formed from thermoplastic fibers such as polyamides, polyesters, acrylics and the like.

Yarns treated according to the invention generally have been previously subjected to one or more stress creating operations. For example, the yarns may be initially drawn or stretched, crimped, false twisted, asymmetrical heated or quenched, etc. Also, the yarns may have been formed with fibers having latent stresses such as bicomponent fibers. The method of the invention is particularly useful wtih yarns in which the latent stresses and strains have been created by a crimping process. As pointed out above, latent stresses may cause excessive shrinkage in fabrics formed from such yarns unless the yarns are uniformly stabilized prior to incorporation into fabrics. The yarn is subjected to a stream of. gas and fed to yarn advancing means in an overfed" and low'ltension condition. The gas stream employed to heat the yarn is, preferably at an elevated temperature'Particularly advantageous is the use of an aspirator device employing hot air or another hot gas. This arrangement not only heats the yarns but also provides the necessary conditions for properly feeding the yarn to the yarn advancing means. Utilizing the aspirator with a heated compressed gas causes the filaments of a multifilament yarn to separate so that the individual filaments can be uniformly heated, thereby inducing a high degree of crimp development and shortening in length. Simultaneously, the aspirating effect provides a convenient means for overfeeding the yarn to a yarn advancing means, that is, the supply speed is greater than the take up speed of the yarn on the yarn advancing means. A pressure between about 5 and psi. for the compressed gas-supplied to the aspirator is desirable.

The yarn is advantageously heated prior to contact with the yarn advancing means to a temperature between about 60 and 425 F. and preferably between about 200 and 375 F. Likewise, the pull-down or shortening of the yarn prior to contact with the yarn advancing means is advantageously between about 5 and 50% and particularly between about and 25%.

The yarn is advanced by contact with a moving surface of the yarn advancing means. The use of a roll r drum in combination with a canted bar or roller to effect advance of the yarn in a generally helical configuration is particularly useful. This arrangement permits a running length of yarn of substantial size to be processed m a limited space while providing sufficient treatment time to effect stabilization and/or setting of the yarn.

The yarn advancing by contact with the moving surface is subjected to a gaseous atmosphere. The term gaseous atmosphere as used herein is intended to include both vapors and true gases, for example, steam, air, nitrogen, argon and similar materials. This treatment desirably is provided over substantially the entire length of the yarn to achieve uniform heating of the yarn. Preferably, the fiow of the gaseous atmosphere is in a direction generally transverse to the path of the yarn being treated. One system for achieving this result is to surround the yarn advancing means with a hot gas distributing means having a plurality of openings or nozzles directed toward the yarn and providing a yarn advancing means with a perforated surface and an internal exhaust so that the flow of the gaseous atmosphere will be substantially transverse to the path of the yarn.

The fiow of the gaseous atmosphere to which the yarn is subjected advantageously is between about 50 and 1000 cubic feet per minute and preferably between about 100 and 500 c.f.m. The temperature when a heated gaseous atmosphere is employed is advantageously between about 200 and 450 C. and preferably at a temperature within about 25% of the melting temperature.

The method of the invention provides for subjecting a textile yarn to a gas stream and shortening thereof prior to being treated with a heated gaseous atmosphere. This results in stabilization of the yarn under controlled conditions with a minimum of tension in the yarn which might otherwise adversely affect previous yarn processing and treatments. For example, yarn which has been latently crimped such as by edge crimping may have the crimp therein developed to a substantial degree and the developed crimp subsequently stabilized so that it will retain its desired configuration in fabrics and other products formed therefrom.

One form of apparatus for conducting a particular embodiment of the present invention is shown in the accompanying drawings in which:

FIGURE 1 is a partially schematic view in perspective of apparatus for drawing, crimping, developing and stabilizing textile yarn, and

FIGURE 2 is an enlarged view of a portion of the apparatus shown in FIGURE 1, partially in section.

As shown in FIGURE 1 yarn 10 is processed in an arrangement including supply packages 11, input rolls l2, draw pins 13, heater strip 14 and guide rolls 16 to draw the yarn. The drawn yarn is then edge crimped with heater rolls 17, blade 18 and cooling rolls 19. The crimped yarn is then passed over guide 21 and processed on a yarn stabilizing device including a drum or roll 22 surrounded by a manifold 23. The manifold has an aspirator tube 24 extending therethrough for feeding a yarn onto drum 22. Aspirator 24 is supplied with heated gas through line 26. Connected to the manifold is a supply chamber 27 which in turn is connected to a fan 28 through a duct 29. Likewise, drum 22 is connected to fan 28 through exhaust chamber 31 and duct 32. Exhaust chamber 31 is disposed about shaft 33 which drives drum 22. Yarn removed from the surface of drum 22 F exits through slot 34 in manifold 23, over guides 36 and 37 and is collected on package 38 driven by roll 39. The take-up includes a traversing guide 40.

As shown in FIGURE 2, within gas supply chamber 27 is disposed a heating element 42 for heating gases moving therethrough. Also, a portion of line 26 is positioned within chamber 27 so that the compressed gas in line 26 may be heated by the hot gas moving through chamber 27.

Manifold 23 has an opening 43 therein providing a connection between chamber 27 and manifold 23. Manifold 23 includes a perforated distributor plate 44 adjacent to the drum 22 for directing a gaseous atmosphere into contact with the yarn. Likewise, peripheral surface 45 of roll 22 has a plurality of openings through which gas can be exhausted. Spaced adjacent to the surface of drum 22 is a canted roller 47 to facilitate advance of the yarn.

In the operation of the apparatus shown in the drawings, yarn 10 is drawn from supply packages 11 onto rolls 12, through guide pins 13 and heater strip 14 and over rolls 16 operating at a speed greater than rolls 12 to draw the yarn under the influence of the heat supplied to the yarn by heater 14. The yarn then passes over heated rolls 17 which heat the yarn prior to its being passed over blade 18. As the yarn leaves the edge of blade 18 it is conducted to rolls 19 which are cooled, preferably with a cooling fluid.

The crimped yarn then moves over guide 21 and is fed onto drum 22 by means of aspirator 24. Aspirator tube 24 is supplied with a heated compressed gas through line 26. The yarn passing through aspirator tube 24 is heated by the hot gas from line 26 and permitted to shorten in length. In the case of multifilament yarns, the action of the hot gas moving through aspirator 24 causes the filaments to separate or open and shorten to produce a bulking effect. The flow of the hot gas through aspirator tube 24 is controlled so that the yarn is fed from the aspirator at a higher speed than it is taken up on drum 22. The yarn is threaded onto perforated surface 45 in a number of helical wraps with each wrap passing over bar 47.

As the yarn advances across drum 22, hot air is forced through the openings in distributor plate 44 of the manifold 23. Since plate 44 almost completely surrounds drum 22 and is perforated with a large number of openings, the flow of hot air or other gas from the openings is generally transverse to the path of the yarn as it is advanced on rotating drum 22. The hot gas, after contacting the fibers, is exhausted through the openings in peripheral surface 45 of the drum 22, into exhaust chamber 31 and through duct 32 to fan 28. The hot gas is recycled by fan 28 through duct 29 into chamber 27 where the temperature thereof is restored to operating conditions by heater 42 disposed within chamber 27. The hot gas after passing heater 42 passes by a portion of line 26 disposed within chamber 27 and thus heats the compressed gas therein. The hot gas moves into manifold 23 through opening 43 which connects manifold 23 with chamber 27. The hot gas is then expelled through the openings in distributor 44 of manifold 23 and against the yarn 10 advancing on the surface 45 of drum 22. The hot gas is again exhausted into the interior of the roll and recycled with fan 28.

The yarn after having the crimp therein developed and stabilized is removed from the surface of drum 22 through slot 34 in manifold 23. The yarn then passes over guides 36 and 37 and is collected on package 38 with guide 40 and roll 39.

The following examples illustrate particular embodiments of the invention and are not intended to limit the scope of the invention in any way.

EXAMPLE I A pair of undrawn nylon 6 yarns each of 68 filaments are combined and processed on apparatus similar to that illustrated in FIGURE 1 of the drawings. The yarn is drawn by passing over input rolls, a heater and onto takeup rolls to a denier of about 2200 for the combined yarns. The drawn yarn is then transferred onto a heater roll, crimped over an edge and passed onto a cooling roll.

The resulting edge crimped yarn is pulled from the cooling roll at a speed of about 275 yards per minute by an aspirator using air at 40 p.s.i. (gauge) and about 380 F. and fed therethrough onto a rotating perforated drum with about 18% overfeed. Ten wraps (approximately 40 feet of yarn) are wrapped onto the roll and air at about 390 F. is passed through the yarn while it is on the roll to develop and stabilize the crimp in the yarn. The air is forced from the openings of a manifold surrounding the roll in an arrangement such as shown in the drawings at about 215 cubic feet per minute. The yarn has approximately 9 crimps per extended inch and a shrinkage of about 16.5% of the original length as measured by the following method. The length of a loop of yarn loaded with 0.2 gram per denier is measured, the load removed, the yarn boiled in water for ten minutes and dried. The yarn is then loaded with 0.002 gram per denier and the length remeasured. The shrinkage is the difference in length. The resulting yarn is suitable for use in carpets by tufting the crimped yarns through a carpet backing.

EXAMPLE H The procedure of this example is the same as that of Example I except that two ends of polyester are used, each having 74 filaments and a denier of about 1330 after drawing. The overfeed through the aspirator is 20%, and wraps (approximately 60 feet of yarn) are wrapped about the roll. The temperature of the air in contact with the yarn is about 370 F. The resulting yarn having a shrinkage of about and about 8.7 crimps per extended inch is useful in the production of carpets.

The above description, examples and drawings show that the present invention provides a novel method and apparatus for continuously and uniformly processing textile yarn in a gaseous atmosphere. Furthermore, the present invention provides for the development and stabilization of latent crimp in yarns by a method and apparatus heretofore not known. Moreover, the method and apparatus of the invention provide a simple and convenient means for uniformly and continuously treating textile yarn in a gaseous atmosphere, particularly a heated gaseous atmosphere.

That which is claimed is:

1. A method for continuously processing a textile yarn while maintaining the yarn under minimum tension conditions, comprising the steps of overfeeding a continuous strand of yarn onto a moving yarn support surface to maintain the yarn under low tension thereon, and advancing the yarn on said surface in a plurality of helical loops through an annular gas treating zone while subjecting the yarn to a gaseous atmosphere.

2. A method as defined in claim 1 wherein the yarn is overfed onto the moving yarn support surface by conveying the yarn onto the surface in a moving stream of gas.

3. A method as defined in claim 2 including the step of heating the moving stream of gas to raise the temperature of the yarn strand being conveyed therein.

4. A method as defined in claim 3 wherein the textile yarn is a thermoplastic yarn, and the strand of yarn is heated in the moving stream of gas under conditions sufiicient to cause significant longitudinal shrinkage of the strand of yarn prior to its contact with the moving yarn support surface.

5. A method of continuously processing a textile yarn according to claim 3 wherein the yarn is crimped prior to being subjected to said gas stream.

6. A method of continuously processing a textile yarn according to claim 2 wherein the textile yarn is subjected to a stress creating processing operation prior to being subjected to said gas stream.

7. A method of continuously processing a textile yarn according to claim 6 wherein the yarn is subjected to asymmetrical heating or quenching.

8. A method of continuously processing a textile yarn according to claim 1 wherein the heated gaseous atmosphere is heated air.

9. A method of continuously processing a textile yarn according to claim 1 wherein a substantially uniform flow of a heated gaseous atmosphere is directed generally transversely to the path of the yarn.

10. A method of continuously processing a textile yarn according to claim 1 wherein the yarn being processed is a bicomponent yarn.

11. A method of continuously processing a textile yarn according to claim 1 wherein the yarn is heated to an elevated temperature and overfed to the yarn advancing means with a stream of heated compressed gas, and a substantially uniform flow of a heated gaseous atmosphere is directed generally transversely to the path of the yarn while it is in a generally helical configuration.

12. A method of continuously processing textile yarn according to claim 11 wherein the yarn is subjected to a crimping step prior to being heated to the elevated temperature, and the heated gaseous atmosphere is heated air.

13. Apparatus for continuously processing a textile yarn comprising a rotatable yarn support drum for supportably receiving a continuous yarn strand on its peripheral surface, gas distributor means surrounding the peripheral surface of said drum to form an annular yarn treating chamber therebetween, means for rotating the said drum to convey a yarn strand in a plurality of loops thereon through said chamber, means for feeding a continuous yarn strand onto the peripheral surface of said drum to maintain the yarn strand under low tension while thereon, and means for introducing a gaseous medium into said annular chamber to contact the yarn on the surface of the drum during its movement therethrough.

14. Apparatus as defined in claim 13 wherein the peripheral surface of said yarn support drum is perforate, said gas distributor means comprises an annular manifold having a perforate inner surface disposed in spaced, surrounding relation to the perforate surface of said drum to form said annular treating chamber, said means for introducing gaesous medium into said annular treating chamber includes conduit means connecting the interiors of said manifold and drum, heating means disposed in said conduit means, and means for circulating gas in a substantially closed path through said conduit means, manifold, and drum, and across said yarn treating chamber disposed therebetween.

15. Apparatus as defined in claim 14 wherein said overfeeding means includes an aspirator communicating with said annular treating chamber, and means for supply ing heated gas to said aspirator, said supplying means including a gas conveying conduit connected to said aspirator and positioned in said conduit means in heat exchange relation with gases passing therethrough.

16. Apparatus for continuously processing a textile yarn according to claim 13 wherein the feeding means is an aspirating means.

17. Apparatus for continuously processing a textile yarn according to claim 13 wherein the apparatus includes yarn crimping means operatively associated therewith.

18. Apparatus for continuously processing a textile yarn according to claim 13 wherein the apparatus includes yarn drawing means and yarn crimping means operatively associated therewith.

FOREIGN PATENTS 1,419,438 10/1965 France.

LOUIS K. RIMRODT, Primary Examiner US. Cl. X.R. 281, 72 

